1. FIELD OF THE INVENTION
The present invention relates to a photoelectric encoder capable of stabilizing the output signal thereof despite the fluctuation of operating conditions.
Photoelectric encoders are widely utilized today due to the noncontact type and a variety of advantages including a small load of a rotator, a capability of high-precision positional detection based on the density of the slits in a disk, a compact and lightweight structure, and high reliability in operation.
2. Brief Description of the Prior Art
In the photoelectric encoder, the light emitting elements employed are primarily LEDs (light emitting diodes) and in some cases, incandescent lamps, while silicon photodiodes are used as light sensing elements. Each of such light emitting and sensing elements is affected by the fluctuation of the power source voltage applied thereto and/or ambient temperature or adhesion of extraneous substances such as dirt and others which eventually vary the output. The output variation thus induced causes malfunction of the circuit in the following stage to render the positional detection inaccurate as a result.